SR-71 Blackbird

Two SR-71 aircraft were used by NASA as testbeds for high-speed, high-altitude aeronautical research. The aircraft, an SR-71A and an SR-71B pilot trainer aircraft were based at NASA's Dryden Flight Research Center, Edwards, Calif. They have been loaned to NASA by the U.S. Air Force. Developed for the USAF as reconnaissance aircraft more than 30 years ago, SR-71s are still the world's fastest and highest-flying production aircraft. SR-71 Home Page

The aircraft can fly more than 2200 miles per hour (Mach 3+ or more than three times the speed of sound) and at altitudes of over 85,000 feet. This operating environment makes the aircraft excellent platforms to carry out research and experiments in a variety of areas aerodynamics, propulsion, structures, thermal protection materials, high-speed and high-temperature instrumentation, atmospheric studies and sonic boom characterization.

Data from the SR-71 high-speed research program may be used to aid designers of future supersonic/hypersonic aircraft and propulsion systems, including a high-speed civil transport.

The SR-71 program at Dryden was part of NASA's overall high-speed aeronautical research program, and projects involve other NASA research centers, other government agencies, universities and commercial firms.

Research at Mach 3

One of the first major experiments to be flown in the NASA SR-71 program was a laser air-data collection system. It used laser light instead of air pressure to produce airspeed and attitude reference data such as angle of attack and sideslip normally obtained with small tubes and vanes extending into the air stream or from tubes with flush openings on an aircraft's outer skin.

The flights provided information on the presence of atmospheric particles at altitudes of 80,000 feet and above where future hypersonic aircraft will be operating. The system used six sheets of laser light projected from the bottom of the "A" model. As microscopic-size atmospheric particles passed between the two beams, direction and speed were measured and processed into standard speed and attitude references. An earlier laser air data collection system was successfully tested at Dryden on an F-l04 testbed.

The first of a series of flights using the SR-71 as a science camera platform for NASA's Jet Propulsion Laboratory, Pasadena, Calif., was flown in March 1993. From the nosebay of the aircraft, an upward-looking ultraviolet video camera studied a variety of celestial objects in wavelengths that are blocked to ground-based astronomers.

The SR-71 has also been used in a project for researchers at the University of California-Los Angeles (UCLA) who were investigating the use of charged chlorine atoms to protect and rebuild the ozone layer.

In addition to observing celestial objects in the various wavelengths, future missions could include "downward" looking instruments to study rocket engine exhaust plumes, volcano plumes and the Earth's atmosphere, as part of the scientific effort to reduce pollution and protect the ozone layer.

The SR-71, operating as a testbed, also has been used to assist in the development of a commercial satellite-based, instant wireless personal comunications network, called the IRIDIUM system, under NASA's commercialization assistance program. The IRIDIUM system was being developed by Motorola's Satellite Communications Division. During the development tests, the SR-71 acted as a "surrogate satellite" for transmitters and receivers on the ground.